Weldolet 72”x24” 2

[insider79]

Hi experts, I am looking for some advise on on weldolets. The client line class specifies a weldolet for 72”x24” run-branch connection. Frankly speaking I have never such a big run size pipe nor such a size combination of weldolet. I’m wondering whether if it is a good idea to use a weldolet considering the challenges in welding. I’m thinking of designing a reducing tee or using pipe to pipe connection. I will talk to some manufactures too. What’s your take on this?

Regards
SH

 

[LittleInch]

Design pressure?

Wall thickness of run pipe?

Fluid?

Remember - More details = better answers
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[MJCronin]

The problem, of course, is that the weldolet is a thick forged piece.

Having facilities available to forge this 72 inch "one of a kind" piping joint will be hard to find.

A quick scan of Bonney Forge Weldolets (and their numerous Chinese counterfeits) shows that they are offered commercially only to 36" NPS

Contact WFI International and talk with them....

http://wfi-intl.com/

For a price, they have been able to produce, code qualified piping fittings for me....

Please Respect us ..... Complete this thread by stating what you have found and how your problem is resolved

MJCronin
Sr. Process Engineer

 

[insider79]

Thanks to both of you for your prompt reply. I will come back with further details on Monday.

 

[LittleInch]

MJC - the branch size is "only" 24". The only thing that the run pipe size impacts is the profile on the integrally reinforced branch fitting to give it its proper name...





Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[insider79]

Based on the latest calculations by process engineer, we wouldn't be needing a 72" line anymore. The max size of the line is 60". the weldolet is 60"x24" with below details:

run pipe size/ WT: 60"/ 17.48 mm
run pipe size rating: CL300.
fluid: process, moderately corrosive-3mm CA

The options that I'm thinking of using are in below order of preference:

1. special tee designed & qualified per ASME B 31.3or other ASME codes as available.
2. pipe to pipe with reinforcement.
3. weldolet.

Please do advice.

Best Regards
SH

 

[LittleInch]

I don't really see what the issue is here?

I would have put weldolet top of the list. Certainly the cheapest.

A 24" into a 60" is less than half the line size. When you get to 70-80% of the run pipe you can bend the pipe alright.

Or try one of Bonney forges "insert weldolets"

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[insider79]

Thanks little inch for you reply.like you said one of my concerns was deformation of run pipe due to heat input resulting from welding the weldolet(I guess that’s what you are referring to as bending?). I’m pleasantly surprised that weldolet is the cheapest. I was wondering forging such a weldolet would cost a fortune. What do you think about pipe to pipe? From the client’s line classes, it doesn’t seem they like pipe to pipe connections.

 

[LittleInch]

Well deformation is an issue but often is when you get only a small difference in branch to run pipe size say 10" x 12" with a big wall thickness or you get a lot of them in short succession (like a manifold) on one side.

Cost is all relative and you need to factor in welding costs and fitting into all of this. Get some quotes and then see.

Pipe to pipe will almost certainly need reinforcement to comply with the B 31.3 design, but you can work it out quite easily. Even then the stress factor at those joints is higher than an integrally reinforced branch fitting (aka weldolet). I agree with your client.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[MJCronin]

I misunderstood, LittleInch, as always gives sage advice ... a 24 x 72 weldolet is common

Insider79 states:

I’m wondering whether if it is a good idea to use a weldolet considering the challenges in welding.

Really ? ... What kind of special knowledge do you have that prevents the use of a weldolet here ?

Like many other fittings, weldolets have to be carefully welded in sequence to prevent distortion.

Weldolets also have a lower code SIF than any other piping fabricated tee intersection .... That is why they were developed and sold !!!

What did Bonney Forge say when you called them ??

Is this yet another example of mid-eastern "whatdoyathink" of "somebodyoncetoldme" engineering?


MJCronin
Sr. Process Engineer

 

[insider79]

@littleinch: thank you for your reply. You have been helpful

@MJCronin: I don't claim to have special knowledge about welding of weldolet, but, I do have the common sense to know that welding a weldolet is not as straight forward as circumferential weld or longitudinal weld given the awkward weldolet profile you will cut on the run pipe. I have been doing some home work myself by reading codes, vendor catalogs and talking to experts. I'm not a big fan of calling the vendor right away without having understood some basic stuff. Regarding your mid eastern engineering comment, if you are talking about my nationality, then I find it racist and take objection to that and there is no place for people like you on this platform. By the way, I am not mid eastern.

 

[DekDee]

insider79
The work in getting a suitable " scallop" preparation on a pipe to pipe joint far outweighs any additional costs for a weldolet.
If they can supply a weldolet for 60" configuration then you just drop it on and weld it.
If they can only supply something close (many weldolets are made to cover a range of run sizes)it will only require minimal grinding to get the required shape.
Or, as per LI's suggestion - an insert weldolet (we call them sweepolets) - if they can supply is the ideal answer.

 

[KevinNZ]

I have seen weldolets used on thin wall mains and the excessive weld puts stress into the thin main pipe wall. In this case a designed reinforcing pad can be a better detail.

 

[KernOily]

I would see if you can get a deviation to the client's specs to use a stub-in (pipe-to-pipe as you refer to it). If you don't have stress problems, and it's not high temperature and/or high pressure, and if the owner permits it, and there are no fatigue issues, a stub-in is perfectly acceptable. Just review the requirements in B31.3 to see if you need a repad. It's done all the time. Yes it has a higher SIF than a WOL; that's why you do the engineering. Downside is a stub-in is dependent on fabrication skill.

For your stress calcs, for a 24 on 60 branch connection I would not use the Code SIF rules and instead use B31J and/or FEA to qualify the connection, then use those SIFs in your pipe stress program.

'The work in getting a suitable "scallop" preparation on a pipe to pipe joint far outweighs any additional costs for a weldolet.' I'm not too sure about that... it would be worth discussing with a good fitter/fabricator. Good pipefitters are fast and can do this all day. You didn't say your location, but if this project is in the Texas Gulf coast then it's no problem; other areas though you might have an issue.

 

[MJCronin]

KevinNZ

Weldolets and Pipets for Schedule 10S piping have existed for many years. You still need a skilled pipe welder ...

https://www.eng-tips.com/viewthread.cfm?qid=358634

http://wfi-intl.com/index.php?page=light-weight-schedule-pipet

MJCronin
Sr. Process Engineer

 

[gtaw]

A branch with a reinforcement pad versus a custom designed and manufactured integrally reinforced branch fitting; that should be an interesting cost analysis.

Best regards - Al